IACR News
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14 October 2022
Marijn F. Stollenga
We introduce Proof-of-Space Search (PoSS) which embraces Hellman's time-memory trade-off to create a much simpler algorithm that avoids the Nothing-at-Stake problem. Additionally, we greatly stabilise block-times using a novel dynamic Logarithmic Embargo (LE) rule. Combined, we show that PoSSLE is a simple and stable alternative to PoW with many of its properties, while being an estimated 10 times more energy efficient and sustaining consistent block times.
Paul Bunn, Eyal Kushilevitz, Rafail Ostrovsky
In this paper, we present a protocol for the NIAR model that improves upon the results from [SW21] in two ways:
- Improved computational efficiency (quadratic to near linear): Our protocol matches the communication complexity of [SW21] for each sender/receiver, while reducing the computational overhead for the router to polylog overhead instead of linear overhead.
- Relaxation of assumptions: Security of the protocol in [SW21] relies on the Decisional Linear assumption in bilinear groups; while security for our protocol follows from the existence of any rate-1 oblivious transfer (OT) protocol (instantiations of this primitive are known to exist under DDH, QR and LWE [DGI19,GHO20]).
Miguel Ambrona, Marc Beunardeau, Anne-Laure Schmitt, Raphaël R. Toledo
Christina Boura, Nicolas David, Rachelle Heim Boissier, Maria Naya-Plasencia
Lucjan Hanzlik, Julian Loss, Benedikt Wagner
In this paper, we introduce a blind signature scheme that eliminates all of the above drawbacks at the same time. Namely, we show a round-optimal, concretely efficient, concurrently secure, and stateless blind signature scheme in which communication and computation are independent of the number of signing interactions. Our construction also naturally generalizes to the partially blind signature setting.
Our scheme is based on the CDH assumption in the asymmetric pairing setting and can be instantiated using a standard BLS curve. We obtain signature and communication sizes of 9KB and 36KB, respectively. To further improve the efficiency of our scheme, we show how to obtain a scheme with better amortized communication efficiency. Our approach batches the issuing of signatures for multiple messages.
Xiutao Feng, Xiaoshan GAO, Zhangyi WANG, Xiangyong ZENG
Hoeteck Wee
Shweta Agrawal, Simran Kumari, Anshu Yadav, Shota Yamada
1. Public Trace Setting: We provide a construction which (i) achieves optimal parameters, (ii) supports embedding identities (from an exponential space) in user secret keys, (iii) relies on polynomial hardness assumptions, namely compact functional encryption (${\sf FE}$) and a key-policy attribute based encryption (${\sf ABE}$) with special efficiency properties constructed by Boneh et al. (Eurocrypt 2014) from Learning With Errors (${\sf LWE}$), and (iv) enjoys adaptive security with respect to the revocation list. The previous best known construction by Nishimaki, Wichs and Zhandry (Eurocrypt 2016) which achieved optimal parameters and embedded identities, relied on indistinguishability obfuscation, which is considered an inherently subexponential assumption and achieved only selective security with respect to the revocation list. 2. Secret Trace Setting: We provide the first construction with optimal ciphertext, public and secret key sizes and embedded identities from any assumption outside Obfustopia. In detail, our construction relies on Lockable Obfuscation which can be constructed using ${\sf LWE}$ (Goyal, Koppula, Waters and Wichs, Zirdelis, Focs 2017) and two ${\sf ABE}$ schemes: (i) the key-policy scheme with special efficiency properties by Boneh et al. (Eurocrypt 2014) and (ii) a ciphertext-policy ${\sf ABE}$ for ${\sf P}$ which was recently constructed by Wee (Eurocrypt 2022) using a new assumption called evasive and tensor ${\sf LWE}$. This assumption, introduced to build an ${\sf ABE}$, is believed to be much weaker than lattice based assumptions underlying ${\sf FE}$ or ${\sf iO}$ -- in particular it is required even for lattice based broadcast, without trace.
Moreover, by relying on subexponential security of ${\sf LWE}$, both our constructions can also support a super-polynomial sized revocation list, so long as it allows efficient representation and membership testing. Ours is the first work to achieve this, to the best of our knowledge.
Trey Li
Dana Dachman-Soled, Huijing Gong, Tom Hanson, Hunter Kippen
Trey Li
11 October 2022
IST Austria, TU Graz, TU Vienna, University of Vienna, University of Klagenfurt
We offer 14 interdisciplinary and interconnected research projects at the intersection of Cryptography, System Security, and Formal Methods. The projects are listed below, each is led by a PI in collaboration with at least another member of the SPyCoDe faculty
- Cross-Layer Security for Blockchain Consensus (Pietrzak, ISTA)
- Cross-Layer Side-Channel Security (Gruss, TU Graz)
- Cryptographic Techniques for Blockchain Security (Andreeva, TU Vienna)
- Cryptographic Techniques for System Security (Eichlseder, TU Graz)
- Enforcement of Security and Privacy Policies across Multi-Party Code (Lindorfer, TU Vienna)
- Formal Verification of Side Channel Properties (Bloem, TU Graz)
- Game-Theoretic Models for Blockchain Applications (Fuchsbauer, TU Vienna)
- Interface Theory for Security and Privacy Employer (Henzinger, ISTA)
- Logic-based Reasoning for Hyperproperties (Kovács, TU Vienna)
- Quantitative and Probabilistic Security Analysis (Oswald, U Klagenfurt)
- Secure Blockchains in Network Transition Periods (Ullrich, U Vienna)
- Secure Network and Hardware for Efficient Blockchains (ISTA, Kokoris-Kogias)
- Security and Privacy by Design for Smart Contracts (Maffei, TU Vienna)
- Side-Channel Resistant System Design (Mangard, Graz)
Closing date for applications:
Contact: Olha Denisova recruiting-questions@spycode.at for questions about the application. Any of the affiliated faculty (https://spycode.at/people/) with questions about their projects.
More information: https://spycode.at/apply/
EPFL, Switzerland
The Laboratory for Computation Security at EPFL, led by Prof. Alessandro Chiesa, is hiring a Cryptography Engineer.
You will join the lab as a full-time developer, and collaborate with other researchers (graduate students and postdoctoral scholars) to create high-quality open-source software that realizes complex cryptographic protocols.
The group's research include, but is not limited to, computational complexity, zero-knowledge proofs, succint non-interactive arguments (SNARGs) and privacy-enhancing technologies (such as peer-to-peer private payment systems and smart contracts).
Responsabilities:- Realizing secure and efficient implementations of new cryptographic protocols
- Developing and contributing to open-source libraries for cryptographic proofs
- Helping prepare pedagogical material (software projects for courses)
- Master's degree in Computer Science (or equivalent engineering experience)
- Experience in software development with Rust and C++
- Knowledge of basic algebra (groups, finite fields, ...) and basic cryptography (hash functions, encryption, ...)
Closing date for applications:
Contact: Alessandro Chiesa
More information: https://recruiting.epfl.ch/Vacancies/2318/Description/2
University of South Florida, St Petersburg, Florida
Closing date for applications:
Contact: Jean-François Biasse
More information: https://www.mathjobs.org/jobs/list/20917
TU Wien (Security and Privacy Research Unit)
Your profile:
- Completion of an appropriate doctorate and in-depth knowledge of the subject area
- An outstanding publication record in top security and privacy conferences
- Research background in one of the following topics: formal methods for security and privacy, blockchain technologies, intersection between machine learning and security or privacy, or web security
- Experience in teaching and publication activities as well as interest and pleasure in research and working with students
- Organisational and analytical skills as well as a structured way of working
- Excellent skills in English communication and writing, knowledge of German (level B2) or willingness to learn it in the first year.
We look forward to receiving your application until 10.11.2022. Applications are only processed online: https://jobs.tuwien.ac.at/Job/194015
Closing date for applications:
Contact: Univ.-Prof. Dr. Matteo Maffei
More information: https://jobs.tuwien.ac.at/Job/194015
Qualcomm Technologies, Inc. - Cork, Ireland
The internship program will skill up the candidate in developing side-channel analysis attacks in the context of post-quantum cryptography, including (but not limited to): literature exploration of most relevant algorithms, open problems, and industry vs. academy gaps; high-performance implementation of state-of-the-art attacks and addition feature to in-house tools.
Minimum qualifications
- Towards the end of M.Sc. or Ph.D. academic degree in Computer Engineering and/or Electrical (or physics) Engineering, or related field
- 6 months is the minimum period for internship program
- Basic knowledge in linear and abstract algebra
- Good knowledge in system-level programming languages (e.g., C, C++, Rust)
- Good communication skills, curiosity and enthusiasm, ability to work independently and willingness to learn
- Knowledge in cryptography and security-related topics (e.g., key management and authentication)
- Good understanding of SoC architecture, ASIC design, and/or hardware security
- Hands-on experience with: VHDL/Verilog, FPGA prototyping, lab equipment
Intern/co-op placement as part of Master/PhD program.
Closing date for applications:
Contact: Santos Merino del Pozo (sdelpozo@qti.qualcomm.com)
Inria Bordeaux
The ANR Project CIAO is looking for a one year postdoc on isogeny based cryptography. The researcher will be working on any area related to this topic: security, implementations, hash functions, key exchange, signature, VDF, higher dimensional isogenies...
The location will be at the Bordeaux Mathematical institute, in France.
https://www.math.u-bordeaux.fr/imb/spip.php?lang=fr
https://www.inria.fr/fr/centre-inria-universite-bordeaux
The application is open and should ideally be filled before April 2023, although an extension should be possible.
The postdoctoral researcher will be part of the LFANT team
https://lfant.math.u-bordeaux.fr/
who develops the Pari/GP software
https://pari.math.u-bordeaux.fr/
If you are interested, please send an email including your CV and a list of publications.
Closing date for applications:
Contact: Damien Robert
http://www.normalesup.org/~robert/pro/infos.html
King's College London
Closing date for applications:
Contact: Martin Albrecht
Barcelona, Spain, 15 February - 17 February 2023
Rabat, Morocco, 29 May - 31 May 2023
Submission deadline: 31 December 2022
Notification: 20 February 2023